Quaternary imidazolium and imidazolinium bisulfites



United States Patent 3,121,091 QUATERNARY llVIIDAZOLIUM AND IMIDAZOLINIUM BISULFITES Jerome Green, Chicago, Ill., assignor to Nalco Chemical Company, Chicago, 111., a corporation of Delaware No Drawing. Filed Mar. 3, 1960, Ser. No. 12,502 1 Claim. (Cl. 260309) This invention relates to quaternary ammonium compounds, and more particularly quaternary ammonium salts of unstable acids which do not exist in pure form.

Quaternary ammonium compounds comprise a class of organic nitrogen compounds of the general structure:

where R R R and R are organic groups of the same and/or different kind, and X is an anion, usually inorganic and most commonly a halide. (N may be a mem ber of a ring in which case the generalized structure must be modified.)

Because of the method of synthesis which is most commonly used in the preparation of quaternaries, the anionic part of the compound is usually a halide. The usual reaction employed is as follows. (This reaction is merely exemplary and is not the only one which has been used.)

While a vast number of combinations of R R R and R are possible, only a comparatively few elements or groups of elements can constitute X in the compound R X in order for the latter to react in the manner indicated.

Thus, most quaternaries of commercial importance are halides, usually chlorides. For various reasons, many of these quaternaries are shipped as concentrated solutions in water or water alcoholv (e.g., isopropanol) solvent. Such solutions are highly corrosive to steel and shipment is ordinarily made in specially lined steel containers or in glass. Even when diluted to use concentrations (usually 0.1 percent and less), aqueous solutions may be objectionably corrosive. Attempts have been made to remedy this property of dilute solutions by using adjuncts such as sodium nitrite, sodium carbonate, and borax. Sodium nitrite has found most favorable acceptance for this purpose. Such corrosion inhibitors vfor the most part either are not compatible with or do not bring about a suitable reduction in corrosivity of highly concentrated quaternary ammonium halide solutions to a point where they can be shipped, stored and handled in contact with ordinary steel.

One of the objects of the present invention is to provide a new and improved quaternary salt wherein an objection-able or less desirable anionic part of a quaternary salt is replaced with an inocuous, beneficial or more desirable one. By the practice of the invention, quaternary halides can be converted to other salts whose solutions are non-corrosive and can therefore be shipped and used without special precautions in this respect.

Another object is to provide new and improved quaternary salts which exhibit novel properties.

in the practice of the invention it is possible to prepare quaternary ammonium compounds in which the anionic part of the molecule is not limited to those heretofore common to such compounds, but is one which confers unique and more desirable characteristics to the compound.

A more specific object of the invention is to provide new and improved quaternary ammonium salts of unstable acids which cannot be isolated in pure form, as, for example, quaternary ammonium salts of sulfurous acid, carbonic acid and nitrous acid.

Another specific object is to prepare new and useful quaternary ammonium salts which are non-corrosive per se and are also effective to inhibit corrosion of metals such as iron and steel when dissolved in normally corrosive liquids which are brought into contact with said metals.

A still further specific object is to provide new and useful quaternary ammonium nitrites, bisulfites, or bicarbouates. Other objects will appear hereinafter.

In accordance with the invention quaternary ammo nium salts containing a predetermined anion as the salt forming constituent are prepared by bringing together a solution of the quaternary ammonium salt dissolved in a solvent and an anion exchange resin which is insoluble in said solvent and contains an anion ditlerent from that of the dissolved quaternary ammonium salt. The invention is especially valuable for converting highly corrosive quaternary ammonium salts to substantially non-corrosive quaternary ammonium salts. :Most of the known quaternary ammonium salts have been prepared in the form of their halides which are highly corrosive, and by the practice of the invention these quaternary ammonium salts are converted to quaternary ammonium salts containing non-corrosive anions, e.g., nitrite, which are not only non-corrosive per se but also have the valuable property of being useful as corrosion inhibiting additives in water, oil and other materials tending to produce corrosion of iron and other metals.

My invention provides quaternary ammonium salts of unstable acids which cannot be isolated in pure form, as, for example, sulfurous acid, carbonic acid, and nitrous acid. To illustrate, nitrous acid, carbonic acid, and sulfurous acid decompose readily upon even slight heating and thus cannot be isolated in pure form as the acid. By the practice of the invention new quaternary ammonium salts of such acids which have new and useful properties can be prepared.

For example,

The principle of the method of preparing the compounds of my invention is given by the following equation:

R+A Q+X- R+X- Q+A- Insoluble Dissolved Insoluble Soluble strong base quaternary strong base quaternary anion exchanger halide (or anion exchanger compound in in desired other salt as halide (or desired salt salt form form) other salt form) form The following conditions preferably employed to carry out the preparation are:

(1) The insoluble anion exchanger is of the strongly basic type. The commercially available ones at present are of the quaternary ammonium .type, e.g., those disclosed in U.S. Patents 2,591,573 and 2,614,099.

The exchanger may be placed in the desired salt form by means well known to those skilled in the art of ion exchange. For example, the exchanger may be treated with an excess of a strong solution of an inorganic salt possessing the desired anion.

(2) The concentration and time of contact of the solution of QH and RA is great enough so that ion exchange will occur. The necessity for these conditions is Well recognized and their selection is accomplished without difficulty. The selectivity or preference of the exchanger for one ion over another is important here. This selectivity characteristic is illustrated in an article entitled Properties of Strongly Basic Anion Exchange Resins by R. M. Wheaton and W. C. Bauman, Industrial and Engineering Chemistry, vol. 43, pages 1088 to 1093 (1951). The higher the K value the greater the preference of the exchanger for that anion as compared with chloride ion. For anions not shown, the general rule is that the higher the valence or negative charge the stronger it is preferred by the resin; the larger the anion, the less it is preferred. These are only rough generalizations. For certain types of anion exchangers, of which Naleite SAR and S312 are examples, the selectivity of the exchanger for various anions is also dependent on the degree of cross-linking of the resin matrix structure. The nature of the solvent system may also be expected to affect selectivity characteristics.

In the practice of the invention, the soluble quaternary salt can be converted to a number of intermediate salts before the one desired is finally made. This can be done, for example, to decrease the difference in selectivity of the insoluble ion exchange resin for the two ions to be exchanged in the final step. Such a procedure illustrates the versatility of the process.

(3) The solvent system is such as to permit sufficient ionization of RA and QH for exchange to occur. This will usually be assured by the presence of relatively small amounts of water. At the same time the solvent system should not dissolve or attack RA and must dissolve QH and preferably QA. While solution of QA is not essential, the formation of a precipitate is likely to clog the resin bed or coat the resin particles and seriously impair the progress of the reaction.

Polar solvents such as alcohols (e.g., methyl alcohol, ethyl alcohol, isopropanol), glycols (e.g., ethylene glycol, diethylene glycol), ketones, aldehydes, and dioxane, can be used to advantage. The proportions of water and solvent will be dependent on the particular conditions which must be met. The organic solvents also have the advantage of reducing the viscosity of aqueous solutions of QH and QA. Evaporation of the solvent to obtain QA in solid form can be carried out, depending on the properties of QA, such as stability.

In general, simple monovalent anions (such as nitrite, for example), will form water-soluble salts with Q. Quaternary salts from more complex and highly charged anions are less soluble in Water, and organic solvent-water systems are advantageous in these cases.

(4) The temperature is limited only by considerations of stability of the system reactants, products, and solvent in the presence of each other.

(5) The operation canbe carried out column-wise or batch-wise. The latter consists of bringing the insoluble resin and solution of QH into contact, separating the two, then bringing the solution into contact with fresh resin and repeating as often as required. Column operation is usually simpler and more efficient and is preferred.

The invention is especially applicable to the synthesis of quaternary ammonium compounds having the following structural formulae in which X represents an anion, more particularly an anion of an unstable acid such as H80 HCO N0 30 or /2CO Class II [Cyclic N eompound:lX-

In the following formulae, R is hydrogen or saturated or olefinic unsaturated hydrocarbyl radical, preferably of 1-17 carbons; R and R are alkyl, alkenyl, hydroxy alkyl, amino alkyl, aryl, or aralkyl; R and R are hydro gen atoms, alkyl, alkenyl, aryl or aralkyl groups.

(A) Inlidazolium N-CRs (C) Pyrrolidinium H20 CH2 (D) Piperidiniunl (F) Morpholinium (G) Isoquinolinium (H) Quinolinium (I) Tetrazolinium The nitrite, bicarbonate, bisulfite, carbonate, or sulfite quaternary salts herein disclosed have many useful applications. They may be employed in place of the chloride ion in quaternary salts to reduce corrosivity toward ferrous metals. They have bactericidal activity toward bacteria such as Aerobacter aerogenes, Flavobacterium and the like. The bisulfites, for example, are oxygen scavengers. The bicarbonates and carbonates can be used instead of the chloride or sulfate quaternary salts in pharmacological preparations.

The best mode contemplated for the practice of the invention will be further illustrated but is not limited by the following examples in which the quantities are stated in parts by weight unless otherwise indicated.

EXAMPLE I This example relates to the use of ion exchange in me paring a new compound tridecyl benzyl hydroxyethyl imidazolinium nitrite having the following structural formula NCH2 013 21 NOT NOH2 CH2 CHzCHeOH The ion exchange resin used in Nalcite SBR, which is a styrene-divinylbenzene resin containing quaternary amine ion exchange groups in which three of the R groups are methyl groups This resin consists of spherical materials of 20 to 50 mesh, cream to pale yellow in color, and containing about 40% water. The divinyl benzene content is approximately 7.5%. The total exchange capacity is approximately 1.2 equivalents per liter wet volume. The K values for this resin are described in the article by Wheaton and Bauman, supra, page 1090, Table II.

The resin is placed in a tube or column'52 inches long and 1.5 inches in diameter. The height of the resin bed is 38 inches, the bed area is 0.0084 square foot and the bed volume is 0.028 cubic foot.

The resin bed is regenerated with a 4% aqueous solu tion of sodium nitrite used at the rate of 13.8 pounds of sodium nitrite per cubic foot of resin. The flow rate during the regeneration is one gallon per minute per cubic foot, and the injection time for the regenerant is 12 minutes.

The regenerated bed is rinsed with 5 gallons of deionized water.

A solution in water of tridecyl benzyl hydroxyethyl imidazolinium chloride is passed through the column of anion exchange resin at a flow rate of 3 gallons per minute per square foot.

The resultant product is an aqueous solution of trimethylbenzyl hydroxyethyl imidazolinum nitrite having the formula given above. This solution can be concentrated or used as such.

The anion exchange resin can be used until the nitrite ion therein has been substantially exhausted as shown by a substantial increase in the chloride concentration of the eflluent from the column of resin.

The percentage conversionof the imidazolinium chloride to imidazolinium nitrite is shown by the following table:

Table I Chloride Concentration of E filueut p.p.m.

Throughput Percent Conversion Ml./0.028 cu. ft.

Gal. cu. ft.

EXAMPLE II A 500 ml. portion of the 10% aqueous solution of the imidazolinium chloride described in Example I is mixed with 150 ml. of the nitrite regenerated anion exchange resin described in Example I for a minimum of 4 hours. The resultant solution and resin are then separated by vacuum filtration. The filtrate is treated in a similar manner with 150 ml of fresh nitrite regenerated anion exchange resin.

The percentage conversion is shown by the following table:

Table II Vol. of 10% Imidazolinium Chloride Chloride No. of Applications of SBR-NOz Percent C onversron 1 Equilibrium is obtained in about 1-2 hours.

Example I illustrate the column or continuous method of preparation and Example 11 illustrates a batch method of preparation. The column method of operation is much more efficient and therefore is preferred.

EXAMPLE III This example illustrates the application of the column method of Example I on a somewhat larger scale with a more concentrated solution of the imidazolinium chloride of Example I.

In this example the column consists of a tank 84 inches high and 12 inches in diameter. The anion exchange resin is the same as that used in Example I and the bed volume is 4 cubic feet.

The regeneration of the anion exchange resin is carried out with a 4% aqueous solution of sodium nitrite at a rate of 10 pounds of sodium nitrite per cubic foot of resin. The flow rate during regeneration is 0.5 gallon per minute per cubic foot of anion exchange resin and the injection time is 50 minutes The anion exchange resin is rinsed with Chicago tap water at a flow rate of 0.5 gallon per minute per cubic foot of resin until the end point is 1 grain per gallon of chloride ion expressed as NaCl.

The same imidazolinium chloride used in Example I is 7 employed except that the concentration is 13.3 by weight in water. The flow rate through the anion exchange resin bed is 3 gallons per minute per square foot. The breakthrough point is approximately 50 grains per gallon of chloride ion expressed as NaCl.

The general procedure is as follows: the anion exchange resin initially in the chloride state is classified by back washing and allowed to settle. The freeboard volume is drained to bed level and the regeneration stated by passing the 4% sodium nitrite solution down-flow through the bed. Following the passage of the regenerant solution a rinse period using Chicago tap water is carried out until the chloride content of the effluent drops to approximately 1 grain per gallon as NaCl, determined titrimetrically.

The freeboard volume is again drained to bed level and the tridecyl benzyl hydroxyethyl imidazolinium chloride is introduced into the unit, filling the freeboard volume, and is passed down-flow through the anion exchanger bed displacing the void volume. When the quaternary ammonium nitrite begins to appear in the efiiuent, the stream is directed to collecting tanks and the effluent is collected until the chloride content reaches approximately 50 grains per gallon expressed as NaCl.

The imidazolinium chloride remaining in the unit at the conclusion of the run is displaced with tap water to a collecting tank and is used to prepare additional quantities of the imidazolinium chloride. When the bed is washed free of the imidazolinium chloride the anion exchange bed is again backwashed and regenerated as previously described. It is then ready for use in the preparation of an additional quantity of the imidazolinium nitrite.

EXAMPLE IV The procedures described in Examples I, II and III are carried out employing a different anion exchange resin, such as Nalcite SAR. This resin is similar to Nalcite SBR except that one of the methyl groups of the ion exchange quaternary salt groups is replaced by hydroxyethyl making the resin somewhat less basic in nature. The K values of this resin are given in the paper by Wheaton and Bauman, supra, page 1090, Table Ill.

EXAMPLE V The procedure is the same as Example I except that sodium bisulfite is substituted for sodium nitrite in chemically equivalent amounts. The product is tridecyl benzyl hydroxyethyl imidazolinium bisulfite.

EXAMPLE VI The procedure is the same as Example I except that sodium bicarbonate is substituted for sodium nitrite in chemically equivalent amounts. The product is tridecyl benzyl hydroxyethyl imidazolinium bicarbonate.

Similarly other quaternary amomnium saits of acids which do not exist in isolated state can be prepared in the practice of the invention.

The invention is especially suitable for converting solvent-soluble quaternary ammonium halides into a quaternary ammonium salt having an anion other than a haiogen atom and especially those having anions whic render the resuitant product non-corrosive.

Specific examples of quaternary ammonium nitrites, bicarbonates, and bisulfites in accordance with the invention are the following:

(1 l) Octadecyl triinethyl ammonium bisulfite (l2) Di-(octadecyl) dimethyl ammonium nitrite l3) Octadecenyl trimethyl ammonium bicarbonate (14) Di-(octadecenyl) dimethyl ammonium nitrite 15) Octadecadienyl trimethyl ammonium nitrite (l6) Di(octadecadienyl) dimethyl ammonium bicarbonate =(17) 1,3-dimethyl-2-heptyl imidazolium bisulfite (18) 1,2-dimethyl-3 heptyl imidazolium bisulfite (19) 1-allyl-3-hepty1-2-methyl imidazolium bisulfite (20) l-benzyl-2-heptyl-3-methyl imidazolium nitrite (21) 1-(2',4'-dichlorobenzyl)-2-heptyl-3-methyl imidazolium nitrite (22) 1-heptyl-2-methyl-3-benzyl imidazolium bisulfite 23) l-heptyl-2-methyl-3 (2',4'-dichlorobenzyl) imidazolium bicarbonate (24) 1,3-dimethyl-2-nonyl imidazolium nitrite (25) 1-methyl-2-nonyl-3-ethy1 imidazolium bicarbonate 26) 1-methyl-2-nonyl-3-allyl imidazolium bisulfite (27) l-methyl-2-nonyl-3-benzyl imidazolium nitrite (28) l-decyl-2,3dimethyl-imidazolium nitrite (29) 1-decyl-2,3-dimethyl imidazolium bicarbonate (30) l-decyl-2-methyl-3-ethyl imidazolium bicarbonate (31) l-decyl-Z-methyl-3-allyl imidazolium bisulfite (32) l-decyl-2-methyl-3-methallyl imidazolium nitrite (33) 1-decyl-2-methyl-3-alphathenyl imidazolium nitrite (34) 1decyl-2-methyl-3-benzyl imidazolium bisulfite (35) 1-decyl-2-methyl-3-benzyl imidazolium bicarbonate (36) 1-decyl-2-methyl-3-benxyl imidazolium bicarbonate (37) 1-decyl-2-methyl-3-(4-chlorobenzyl) imidazolium nitrite (38) 1,3-dimethyl-2-undecyl imidazolium nitrite (39) 1-methyl-2-undecy1-3-rnethallyl imidazolium nitrite (40) 1-methyl-2-undecyl-3-benzyl imidazolium bisulfite (41) 1-methyl-2-undecyl-3-(4'-nitrobenzyl) imidazolium bicarbonate (42) l-amyl-2-undecyl-3-methyl imidazolium bicarbonate (43) 1-amyi-2-undecyl-3-benzyl imidazolium bicarbonate (44) l-tetradecyl-2,3-dimethyl imidazolium bisulfite (45) l-tetradecyl-Z-methylG-bcnzyl imidazolium nitrite (46) 1,3-dimethyl-2-hepty1 imidazolinium bisulfite (47) l-methyl-2-heptyl-3-(2'-chlorobenzyl) imidazolinium nitrite (48) 1-heptyl-2-methyl-3-bcnzyl imidazolinium nitrite (49) l-benzyl-2-methyl-3-octyl imidazolinium nitrite (50) 1,3dimethyl-2nonyl imidazolinium bicarbonate (51) l-methyl-2-nonyl-3-methallyl imidazolinium nitrite (52) 1-methyl-2-nonyl-3-benzyl imidazolinium bicarbonate ate

(59) l-amyl-2-undecyl-3-(2-chlorobenzyl) imidazolinium bisulfite (60) l-dodecyl-2,3-dimethy1 imidazolinium bisulfite (61) l-dodecyl-Z-methyl-S-benzyl imidazolinium nitrite (62) 1-dodecyl-2-methyl-3 (4-chlorobenzyl) imidazolinium bicarbonate (63) 1-tetradecyl-2,3-dimethyl imidazolinium bicarbonate (64) 1-tetradecyl-2-methyl-3-methallyl imidazolinium nitrite 1-decyl-2,3-dimethyl imidazolinium bisulfite 1-decyl-2-methyl-3-benzyl imidazolinium nitrite 1-decyl-2-amyl-3-methyl imidazolinium bisulfite 1-methyl-2-undecyl-3-benzyl imidazolinium nitrite 1-amyl-2-undecyl-3-methyl imidazolinium nitrite 1-amyl-2-undecyl-3-benzyl imidazolinium bicarbonl-tetradecyl-2-methyl-3-benzy1 imidazolinium nitrite 1-benzyl-2-methyl-3-octadecyl imidazolinium nitrite Lauryl isoquinolinium bicarbonate Cetyl isoquinolinium bisulfite Lauryl isoquinolinium bicarbonate Di-coconut dimethyl ammonium nitrite (71) Coconut trimethyl ammonium nitrite (72) Ailtyl (C H to (3 1-1 dimethyl-3,4-dichlorobenzyi ammonium nitrites and alkenyl (C to C dimethyl ethyl ammonium nitrites in the ratio 5:1

19 (73) Di-isobutyl phenoxy ethoxy ethyl dimethyl benzyl SBR can be used for days at temperatures of 50 C. to ammonium nitrite having the formula 60 C. but become markedly less stable at temperatures i t t CHs(|3CH2-(|3C OCH2CH2OCH2CHi1TT-OH2-C N02" cm (1113 CH:

(74) Di-isobutyl cresoxy ethoxy ethyl dimethyl benzyl above 150 C. The stability of the insoluble resin also ammonium bicarbonate, monohydrate having the forvaries, depending upon the particular anion. The resins mula must be treated to introduce the desired anion into the (75) Alkyl dimethyl benzyl ammonium bisulfite having resin before a soluble quaternary ammonium salt disthe formula solved in a solvent is brought into contact with the resin OH in the practice of the invention.

2 To illustrate the advantages of the invention, aqueous solutions of the quaternary ammonium salt used as a starting material in Example I, i.e., aqueous solutions of tridecyl benzyl hydroxyethyl imidazolinium chloride, are very corrosive to steel and therefore cannot be transported CH3 R:mixture of a-lkyl radicals CBHI'Z-CISHS'i, principally CmHaa (76) N-soya-N-ethyl morpholinium nitrite in ordinary steel drums but are normally transported in OH2OH glass containers or carboys. However, aqueous solutions N G H t of the tridecyl benzyl hydroxyethyl imidazolinium nitrite 12 2;, 0 (1131137 N02 \OH 0% \G H produced as described in Example I are non-corrosive and 2 2 5 can be transported in ordinary steel drums. This is of (77) Octadecenyl-9-dimethyl benzyl ammonium nitrite great importance from the practical standpoint. The addi- (78) 1-dodecyl-4-benzyl pyridinium bicarbonate tion of corrosion inhibitors such as disodium orthophos- (79) l-met'nyl-Z-ethyl piperidinium bisulfite phate, monosodiurn orthophosphate, sodium nitrite, sodi- (80) 2-phenyl-3-alpha-naphthyl-S-N-undecyitetrazohum urn carbonate, sodium polyphosphates, sodium silicates, bicarbonate and sodium tetraborate to quaternary ammonium halides (81) Methyl quinolinium nitrite in order to decrease the corrosive action of such halides is (82) Benzyl quinolinium bisulfite not ordinarily satisfactory because many well known cor- (83) 1(3,3-d1phenylpropyl) -1-methyl pyrrolidmium rosion inhibitors either are inellective to prevent corrosion nitrite or cause precipitates which contaminate the product and (84) Hexadecyl pyridinium bisulfite are undesirable. Many of the ordinary corrosion inhib (85) Benzyl trimethyl ammonium nitrite itors are incompatible with the quaternary ammonium salt A special class of new compounds prepared by the because of the formation of these precipitates. A mapractice of the invention is the nmdazolmium mtntes havterial 1s considered to be incompatible when the amount ing the general formula of precipitate formed is greater than that formed in the NQ R3)2 untreated solution. As an example a 10% solution of y N (13(3) NO tridecyl benzyl hydroxyethyl imidazolinium chloride was 4 2 2 R treated with various well known types of inorganic corrosion inhibitors in various amounts and the resultant solution examined for precipitation after 24 hours. Static corrosion tests were run on some of these solutions at room temperatures (20 0). Two mild steel panels, one inch by two inches, were suspended in 200 m1. of the solution. A weighed panel was completely immersed and another was partially immersed. The corrosion rate was determined for the totally immersed panel. The water line attack was observed on the other panel. The results were as follows:

wherein R is hydrogen or a hydrocarbyl radical, preferably a higher aliphatic hydrocarbon radical containing 8 to 18 carbon atoms '(e.g., nonyl, undecyl, tridecyl, pentadecyl, heptadecenyl); R and R are alkyl, preferably methyl, ethyl, propyl, isopropyl, butyl or isobutyl, aryl, preferably phenyl, or tolyl, aralkyl, preferably benzyl, hydroxyalkyl, preferably hydroxyethyl, hydroxypropyl, or hydroxybutyl, aminoalkyl, preferably C H NH 2H4NH.C2H4NH2, 0r C3H6NH2, and R3 and R4 are hydrogen, lower alkyl (e.g., methyl, ethyl, propyl, butyl,

isopropyl, isobutyl), aryl, preferably phenyl or aralkyl, Corrosion Degree 3 preferably benzyl, said compounds containing atoms from Treatment Rate m of w r. itate the group consisting of carbon, oxygen, hydrogen and lag k Fmmed nitrogen. A preferred subclass of such compounds is one in which R is a higher aliphatic hydrocarbon radical, None 3 5 Severe saturated or unsaturated, containing 8 to 18 carbon atoms, ,200 ;.;;'i-it;ni 'o;; 1151)653535'."

one of the radicals R and R is a benzyl group and the 5 mild-m other is a lower aliphatic group containing not more than Nana 0 4-1150; 2.8 (1o yes.

4 carbon atoms, the remaining atoms being from the group fi P6 6 150 es consisting of nitrogen, oxygen and hydrogen, and R and 300 im. learner-1355557151. y

R are hydrogen or lower alkyl groups. ig g gfi' O 200 P 3 8 mild G5 The temperatures used in the process should be above 600 m iyggn'rogg oo'iifiioi' y the freezing point of the solvent and below temperatures gggzgOi-Hm 1,200 .m. 8 0 Severe -y at which the insoluble anion exchanger tends to decompose 2,400 p.p."5."1 r51 fo;l5 ii iI 013 1111- or lose its capacity. Ordinarily, the ion exchange reaction $88 fi g i & m

is preferably carried out at room temperatures around 20 Nal (& iJ 7%), a pip. I Y s.

C. but higher temperatures can be used, depending upon 5 i g g (P1189) the stability of the insoluble anion exchange resin and that 3:53 zgfwl gfifijjjj I: 5 5

of the desired quaternary ammonium salt. Some of the 200119111 NazBtOrlOHzO anion exchange resins such as Nalcite SAR and Nalcite 1 i It will be noted that most of the treatments used were incompatible with the quaternary ammonium chloride at the particular concentrations of each employed. Furthermore, although 2400 parts per million of sodium nitrite l 2 resin cannot be treated directly with a salt in order to introduce the anion. In order to introduce anions of suitable acids such as the nitrite anion into a weakly basic anion exchange resin, the hydroxide form of the resin is decreased the corrosion rate of a completely immersed 5 first converted to the chloride form by treatment with byspecimen to a satisfactory level, the attack at the water line drochloric acid and the chloride form of the resin is then was severe. This line is present in any partially filled converted to the nitrite form by treatment withanaqueous container. On the other hand, the nitrite of Example I solution of sodium nitrite. produced no attack at the water line as shown by the fo Another disadvantage of the weakly basic resins is the lowing comparative test results between the tridecyl benzyl tendency of their salt forms to hydrolyze to the hydroxide hydroxyethyl imidazoliniurn chloride and the nitrite carform. This makes it desirable when using such anion ried out in the same manner: exchange resins :to operate under acidic conditions. The

Composition of Solution Totally Immersed V Partially Immersed Specimen (10% by wt.) Specimen Test No.

Percent Percent Duration Weight Rate of Weight Rate 1 of Magnitude of NOzof Test, Loss, Attack, Loss, Attack, Water Line Form by Form by days mg. MPY mg. MPY Attack Volume Volume 100 0 11 41. 7 2v 22 83.7 3. 5s Faint.

98.75 1. 25 11 04. 7 3. 44 107. 8 4. 58 Do. 03.75 6.25 11 93.3 4.00 137.0 6.49 Moderate. 87. 5 12. 5 11 132. 1 7. 03 158.0 7. 47 Do. 75.0 25.0 11 20.0 1.10 121.3 5. 74 Vcryhcavy. 50.0 50.0 11 1.0 0.00 20.9 0.00 Concentrated at one point. 25.0 75.0 11 1.0 0.10 0.0 0.43 None.

1 Only the area exposed to the test solution was used in calculating the rate of attack.

Not only is the compound of Example I less corrosive to steel containers than the tridecyl benzyl hydroxyethyl imidazolinium chloride but it also acts as an inhibitor when used in small amounts to retard or prevent corrosion when added to burning oils, diesel fuels, kerosene, gasoline, and crude petroleum coming from the Well, and functions to prevent attack of oil and gas well equipment when added in down-the-hole treatments.

Concentrations of 4 to 16 parts per million of tridecyl benzyl hydroxyethyl irnidazolinium nitrite killed Aerobacter aerogenes and two species of Flavobacterium after one hour of contact.

The invention is not limited to the employment of a particular insoluble anion exchange body. However, the use of a strongly basic insoluble anion exchange body has the distinct advantage that the soluble quaternary ammonium salt, for example, a soluble quaternary ammonium chloride, can be converted directly to a quaternary ammonium salt having a different anion. The expression strongly basic anion exchange resin is employed herein to describe an anion exchange resin which is capable of converting salts directly to hydroxides. Thus, a strongly basic anion exchange resin is capable of converting an aqueous solution of sodium chloride directly to an aqueous solution of sodium hydroxide.

In general, a strongly basic ion exchange resin is one which on titration with hydrochloric acid in water free from electrolytes has a pH above about 7.0 when the amount of hydrochloric acid added is one-half of that required to reach the inflection point (equivalence point). A weakly basic ion exchange resin under the same conditions has a pH below about 7.0 when one-half of the acid required to reach the equivalence point has been added. Weakly basic anion exchange resins do not function to accomplish this result but Weakly basic anion exchange resins can be used to effect the end resuLt by an indirect procedure.

One of the difliculties in using weakly basic anion exchange resins in the practice of the invention is the introduction into the resin of the anion Which it is desired to exchange. If the weakly basic resin is in the hydroxide form, anofller anion can be introduced into the resin by regenerating it with an acid. For example, the chloride anion can be introduced by treating the hydroxide form of the resin with hydrochloric acid. The nitrite anion can be introduced by treating the hydroxide form of the resin with nitrous acid. However, the hydroxide form of the use of acidic conditions for optimum results is not a limitation of the strongly basic anion exchange resins.

In order to obtain the optimum results the afiinities of the insoluble resin for the respective anions to be exchanged between insoluble resin and the dissolved quaternary ammonium salt, on the one hand, and between the exhausted insoluble resin and the dissolved regenerant on the other are important in determining the efi'iciency of the process described in this invention. If these aflinities are greatly dilferent, the displacement from the resin of the anion for which it has the greater lafimity by the one for which it has the lesser amnity will be accomplished with difiiculty. While this dilficulty can be overcome in part by appropriate selection of concentrations of dissolved quaternary ammonium salt or regenerant, it is preferable in the operation of this invention that the afiinities of the resin for the anions to be exchanged do not differ by more than ten-fold, as measured by their selectivity constant (K values). In other words, the ratios of the selectivity constants of the anions to be exchanged should be within the range of 10:1 to 1:10. Greater differences are permissible but cause decreasing efficiencies either in conversion of the quaternary ammonium salt or insoluble resin to the salt form desired. For example, Nalcite SAR and Nalcite SBR have very much greater afiinities for salicylate ions than chloride ions. The passage of a solution of sodium saiicylate through a bed of either of these resins in the chloride form converts the resin to the salicylate form with extreme case. However, when a solution of quaternary ammonium chloride is passed through a bed of the salicylate form of the resin only a small percentage of exchange occurs. On the other hand, Nalcite SAR and Nalcite SBR have about the same afiinities for chloride ions as for nitrite ions and the percentage of exchange both in regeneration of the res n by sodium nitrite and in exhaustion of the resin by the aqueous solution of quaternary ammonium chloride is high.

Examples of weakly basic anion exchange resins which can be employed in the practice of the invention are those described in U.S. Patents 2,582,098, 2,597,439 and 2,597,491. Examples of strongly basic anion exchange resins which can be employed in the practice of the invention are those disclosed in U.S. Patents 2,591,573, 2,597,440, 2,597,494, 2,614,099, 2,630,427, 2,632,000 and 2,632,001.

The strongly basic insoluble anion exchange resins which are preferably employed for the purpose of the invention are reaction products of a tertiary alkyl amine and a vinyl aromatic resin having halo methyl groups attached to aromatic nuclei in the resin. Another class of anion exchange resins suitable for the practice of the invention are the reaction products of tertiary carbocyclic or heterocyclic amines and vinyl aromatic resins having halo methyl groups attached to aromatic nuclei in the resin. The vinyl aromatic resins employed as starting materials in making the anion exchange resins employed in the preferred practice of the invention are the normally solid benzene-insoluble copolymers of a monovinyl aromatic compound and a polyvinyl aromatic compound containing from 0.5 to 40% by weight, preferably from 0.5 to 20% by weight of the polyvinyl aromatic compound chemically combined With the monovinyl aromatic compound. Examples of suitable monovinyl aromatic compounds are styrene, alpha methyl styrene, chlorostyrenes, vinyl toluene, vinyl naphthalene, and homologues thereof, capable of polymerizing as disclosed, for example, in US. Patent 2,614,099. Examples of suitable polyvinyl aromatic compounds are divinyl benzene, divinyl toluene, divinyl xylene, divinyl naphthalene and divinyl ethyl benzene. These resins are halo methylated as described, for instance, in US. Patent 2,614,099, preferably to introduce an average of 0.2 to 1.5 halo methyl groups per aromatic nucleus in the copolymer and then reacted with a tertiary amine to introduce a quaternary ammonium anion exchange group. Examples of suitable tertiary amines are trimethyl amine, triethyl amine, tributyl amine, dimethyl propanol amine, dimethyl ethanol amine, methyl diethanolamine, 1-methylamino-2,3- propane diol, dioctyl ethanolamine, and homologues thereof.

The weakly basic resins are prepared in a similar manner except that primary and secondary amines are reacted with the halo alkylated resin. Examples of such amines are methyl amine, dimethyl amine, N-butyl amine, dibutyl amine, isobutyl amine, aniline, benzidines, toluidines, xylidines, alpha and beta naphthalene, naphthalene diamines, benzyl amine, dibenzyl amine, ethylenediarnine, cyclohexylamine, dicyclohexylamine, diethylene triamine, triethylene tetramine, tetraethylene pentamine, propylene diamine, dipropylene triamine, and homologues thereof. The anion exchange resins can also be prepared by halogenating the molecule of the resin and then introducing an anion exchange group as described in US. Patent 2,632,000.

Throughout the specification and claim the terms alkyl and alkenyl are intended to define an aliphatic hydrocarbon radical, either saturated or unsaturated, branched chain or straight chain, for example, methyl, ethyl, propyl, butyl, amyl, hexyl, heptyl, octyl, nonyl, decyl, undeceyl, lauryl, tridecyl, myristyl, cetyl, stearyl, propenyl, allyl, oleoyl, linoleyl, ricinoleyl, linolenyl, and homologues thereof.

The term aminoalkyl refers to an alkyl group containing an amino substituent substituted for at least one hydrogen atom of an alkyl group.

The term hydroxyalkyl refers to an alkyl group containing a hydroxyl group substituted for at least one hydrogen atom (e.g., hydroxyethyl, hydroxypropyl, and homologues thereof.)

The term aryl is used herein to define aromatic carbocyclic groups derived from aromatic hydrocarbons by the removal of one hydrogen atom, for example, phenyl, naphthyl, tolyl, xylyl, and homologues thereof.

The term aralkyl is used to define a radical derived by the removal of a hydrogen atom from an aliphatic side chain attached to an aromatic hydrocargon, for example, benzyl, phenyl ethyl, phenyl propyl, cinnarnyl, and homologues thereof.

The term hydrocarbyl is used to describe a group which is a monovalent hydrocarbon group.

The selectivity constants for various anions can be determined as described by Wheaton and Bauman, supra, for determination of the equilibrium value K,,.

The present application is a continuation-in-part application of my copending application, Serial No. 546,857, filed February 13, 1956, which in turn is a continuationin-part of my copending application Serial No. 367,767, filed July 13, 1953, both of which are now abandoned and are incorporated herein by reference as fully as if they had been set forth in their entirety.

The invention is hereby claimed as follows:

An aqueous solution of a quaternary ammonium compound selected from the group consisting of (I) /N-CH and wherein R is selected from the group consisting of hydrogen, a saturated hydrocarbon group of l-l7 carbon atoms and an olefinically unsaturated hydrocarbon group of 1-17 carbon atoms, R is selected from the group consisting of lower alkyl, lower alkenyl, and monohydroxy lower alkyl, and R is a member selected from the group consisting of benzyl and lower alkyl.

References Cited in the file of this patent UNITED STATES PATENTS 2,493,319 Shonle et al. June 3, 1950 2,590,126 Robinson Mar. 25, 1952 2,713,581 Pannone et al. July 19, 1955 2,738,325 Rydell Mar. 13, 1956 2,842,546 Lane July 8, 1958 2,870,153 Heininger Jan. 20, 1959 2,875,210 Bollenback et al Feb. 24, 1959 2,886,574 Aspergren et a1. May 12, 1959 2,909,525 Fand Oct. 20, 1959 OTHER REFERENCES Handbook of Chem. and Physics (Chem. Rubber Pub. Co., 24th ed.), pp. 394-395 (1940).

Wietzel et al.: Chem. Abstracts, vol. 50, col. 16528 (1956).

Chem. Abstracts Index, vol. 50, p. 12615 (1956).

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,121, o91 February 11 M1964 Jerome Green I It is hereby certified that error appears in the above numbered petent requiring correction and that the said Letters Patent should read as corrected below Column 9, lines 17, to 21, the right-hand portion of the formula reading ]HS read 11 150 column 13, line 55, for '"oleoyl" read oleyl column 14 line 62, under "References Cited"., "for "p.126l5" Read p, 12615 Signed and sealed this 21st day of July 1964., (SEAL) Attest:

ESTQN G. JOHNSON EDWARD J BRENNER Attesting Officer Commissioner of Patents UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,121,091 February 11, I 19641 Jerome Green I It is hereby certified that error appears in the above numbered patent req'liring correction and that the said Letters Patent should read as corrected below.

Column 9, lines 17 to 21, the right-hand portion of the formula reading 1115 read ]HS'O column 13, line 55, for "oleoyl" read oleyl column 14, line 62, under "References Cited", ."for "p. 12615" read p. 12615 Signed and sealed this 21st day of'July 1964.

(SEAL) Attest:

ESTON G. JOHNSON EDWARD J BRENNER Attesting Officer Commissioner of Patents 

